The invention relates to an electric motor provided with an electromagnetic brake having the ability to provide increased braking force to effect an efficient braking action.
An electric motor with an electromagnetic brake is known (GB 920,485) in which the stator has two poles each having a pole shoe projecting to the inside and surrounded by the stator winding. The brake means comprises a brake element for braking of the rotor of the electric motor in which the brake is located symmetrically within one pole and is subjected to a braking force towards the middle. The brake element can be adjusted against the braking force by the magnetic field of the stator winding. The disadvantage in this arrangement of the brake element within the pole is that this arrangement does not permit high disengagement forces so that the brake element can only be provided with a relatively small braking force. The maximum attainable braking action of the brake means is therefore small such that the brake means is not suitable for use in angle grinders.
The electric motor of the invention is provided with an electromagnetic brake means that has the advantage of ensuring application of a high disengagement force so that a high braking force can be achieved resulting in a correspondingly good braking action. By constructing the brake element as a rocker upon which the braking force acts outside the pivoting axis of the brake element, the level of the disengagement force can be greatly increased. A brake means so constructed is thus much more efficient and is also suited for use in angle grinders.